SCHUYLKILL PERMANENT BRIDGE. I7 



compared to these floats, and more easily secured) were 

 swept away by a summer fresh; though they had been 

 supported by some piles, and lYioored with anchors and 

 cables, capable of holding a stout frigate. The levell- 

 ing the bottom, or making one artificially (as was done 

 by Semple at the Essex bridge in Dublin) was found 

 impracticable, on account of the thick cover (13 feet) 

 of mud in some parts, and the total bareness and un- 

 evenness of the rock in others. It became a choice of 

 difiiculties ; and the coffer dam^ or no bridge, was the 

 alternative. Projects easily and cheaply to be accom- 

 plished in shallow streams, with level bottoms, or those 

 capable of being artificially made so, were all found im- 

 practicable, and to the last degree imprudent here. The 

 modes pursued in Nexv England^ either of piles, 

 wharves, log frames, or stones loosely thrown into the 

 stream, w^ere considered and condemned. The destruc- 

 tion of many of the bridges of that country was predict- 

 ed ; but with a hope that this apprehension might prove 

 unfounded, as the enterprizes of the people there were 

 admired and applauded. Sounds^ or arms of the sea, 

 sheltered from violent storms, broad rivers, capable of 

 holding piles, and affording extensive flats, for overflows 

 and waste of floods ; will admit of slighter foundations, 

 though always exposed to danger, under uncommon 

 circum.stances. Many of the sites of eastern bridges 

 are of this description. 



The pressing necessity for some permanent structure, 

 called the attention of many citizens to the subject. 

 But none, for a long course of time, attempted any de- 

 cidedrneasure, till the one whose endeavours where final- 

 ly crowned with success, in the accompli tihment of the 



